Notes: This weapon is the only blowback machinegun to see serious use by any country. This would normally lead to a fast, uncontrollable rate of fire; however, the Schwarzlose used a very heavy breech block and a toggle lever to create an actual mechanical disadvantage to dramatically slow the rate of fire. The first models, the M/05 and M/07, used an oil pump to lubricate the cartridges as they were loaded into the chamber; by 1912 and the M/07/12. this was realized to be unnecessary, and a little more weight was added to the breech block to force dry rounds into the action. One advantage to the blowback system is that it is mechanically simple; the disadvantage in a machinegun is that it is heavy. The Austo-Hungarians used the weapon in 8mm Austrian Service chambering. The Germans also used the Schwarzlose in World War 1, chambered for 8mm Mauser; the Greek and Dutch armies also used the Schwarzlose, the Greeks in 6.5mm Greek Service, and the Dutch in 6.5mm Dutch Mannlicher. The Hungarians and Italians used it as late as 1945, in 8mm Mauser.